Thin sheet blanking mechanism



Patented Mar. 1, 1938 UNITED STATES PATENT OFFICE THIN SHEET B LANKING IMECHANISM Isaac L, Wilcox, Fulton, N. Y., assignor to Oswegb FallsCorporation, Fulton, N. Y., acorporatlon of New York This inventionrelates to cutting mechanism for forming blanks of thin sheet material.More particularly, the invention is a cutting mechanism particularlyadapted to operate upon sheet material which is exceptionally thin, andwhich has the characteristic of possessing exceptionally high tensilestrength until the sheet has been punctured, or ruptured, and whichsheet possesses the further characteristic of being particularlyrelosistant to being cut or sheared. These characteristics of thematerial make it exceedingly difficult to cut or blank with theconventional punch and die structure. Certain cellulose materialspossess this characteristic, For example, Cello- 15 phane.

Insofar as I am aware, the only practical method employed at the presenttime for forming blanks of such material is to employ a rotating knife.That is, the material is first cut into 20 sheets of approximately thesize of the blank, and

, several of these sheets are arranged in stack formation and while sopositioned, a rotating knife is moved into engagement with the stack,and the blanks are cut by the circular'motion of the knife. 25 Whilethis method is practical, insofar as the severance of the blanks fromthe material is concerned, it is impractical in that the severed blanksof this exceedingly thin and slippery material must be subsequentlyhandled individually during 30 the conversion of the blank into thearticle for which the blank is intended.

The general object of'my invention is a cutting mechanism ofparticularly economical construction and which, because of its novelstruc- 35 ture, will efllciently sever individual blanks from the sheetmaterial, and which operates to sever a large volume of blanks withoutthe necessity of resharpening or replacing the cutting blade.

Another object ofthe invention is a cutting 40 mechanism for formingblanks of such material, which mechanism is so constructed that it isadapted for use on the blank converting machine, such as shown in mycqpending application, Sr. No. 105,411 filed October 13, 1936, therebyavoiding the necessity of manually, or otherwise, handling the blankafter it has been severed from the sheet.

The invention consists in the novel features and 50 in the combinationsand constructions hereinafter described and claimed.

In describing this invention, reference is had to the accompanyingdrawing in which like characters designate corresponding parts in allthe 55 views.

Figure 1 is a partial plan view of the cutting mechanism. 1

Figure 2 is a cross sectional view.

Figure 3 is a fragmentary, enlarged cross sectional view. f 5 Figure 4is a fragmentary elevational view of the cutting blade.

The invention comprises generally, a die member of annular formationadapted to support the sheet, and being provided with an aperturecomplemental to the contour of the blank, a cutter support, said die andsupport being arranged to have relative axial movement, a bladedetachably secured to said support and extending therefrom toward thedie, the extending edge of the blade being provided with a plurality ofteeth arranged, upon contact of the blade with the sheet, to penetratethe sheet at a plurality of points, and to subsequently sever the sheetintermediate the penetrations.

The mechanism here shown is used to sever a blank in the form of a diskfrom sheet material, and comprises a die member In and a cutter support'I I. The die and support are arranged to have relative axial movement.As here shown, the die support III is intended to be mounted upon astationary part of the machine, and is provided with diametricallyopposed. bosses l2, in which bushings l3 are inserted. The support II isprovided with similar bosses ll in which are secured guide pins l5 whichare slidably mounted in the bushings l3 and which are connected at theirlower end to connecting rods l6 associated with the movable mechanism ofthe machine. Insofar as this invention is concerned, any conventionalmechanism may be'employed to effect relative axial movement between thedie it and the support H, or to move the support ll axially of the die"I. 4

The die is provided with a centrally arranged 40 aperture I1, and thesupport H with a similar aperture It. The under side of the support I Iis formed with a counterbore arranged concentrically of the aperture l8,and in which is mounted a circular cutter blade 20 which is preferablyformed of thin, flexible steel. The blade 20 may be of annularformation, or it may consist of a flat blade bent into circular form.The blade 20 is detachably secured in the counterbore of the support IIby an expansible ring 2|, here shown as being split at one side as at22, and being expanded by a tapered pin 23. The ring 2| is expanded topress the blade 20 radially outwardly against the counterbore in thesupport II, and the blade is thus rigidly but detachably secured to thesupport, and extends downwardly from the support toward the suHace ofthe die III. I

A presser member 24, in the nature of a ring,

encircles the blade 20 and is carried by one or more studs 25 slidablymounted in the support I I. The presser ring 24 is urged outwardly byhelical compression springs 23 encircling the studs 23, and thearrangement is such that normally, or when the die I0, support ii, arein spaced apart relationship, the presser ring 24 encircles the loweredge of the blade 20 and extends downwardly a short distance therefrom.

The presser ring 24 may be formed with an annular rib 21 on its underside adjacent the bore of the ring, as shown in Figure 3, and the faceof the die toward the upper side of a wear ring 23 formed with acomplemental annular recess 28. As the support II is moved toward thedie III, the rib 21 contacts the sheet 30 press-.- ingthe same into therecess 29. This action tends to draw the sheet taut, and it is held inthis condition by being clamped between the presser ring 24 and the wearring 23 of the die. Upon further downward movement of the blade carrierii, the blank is severed from the sheet.

The lower or extending edge-of the blade 20 is formed with a pluralityof teeth 32. The teeth 32 resemble generally the teeth of a saw, and areformed or arranged with the points 33 of the teeth extending in the samedirection. That is, the forward side 34 of the teeth extend in angularrelationship to the axis of the blade, and the rear side 33 extends atan appreciably greater angle, whereby the points 33 of the teeth arearranged to one side of the perpendicular drawn from the base of theteeth.

The hardened wear ring 28 is of such dimensions as to receive thetoothed edge of the blade 20 upon movement of the support towards thedie. The presser ring 24 engages the sheet and clamps the marginalportion of the same against the ring 28, as above described. Uponfurthermovement of the support, the ends 33 of the teeth puncture or penetratethe sheet, and upon further-movement of the support and blade 20, theknife edges 35 of the teeth sever the sheet intermediate thepenetrations. Due to the fact that the points 33 of the teeth extendforwardly of the base of the teeth, the sheet is completely severedbetween the penetrations.

. Due tothe fact that the blade initially only penetrates the sheet withthe sharp points 33 of the teeth, very little pressure is establishedbetween the support and the die, with the result that the cuttingmechanism may be of comparatively light construction and require littlepower for operation. With these advantages, the cutting mechanism isadapted to be incorporated in the blank converting machine. Attention isparticularly called to the fact that with this mechanism, both the dleand the support i I may be of annular formation permitting the entireinterior of the die and support to be open for subsequent operation ofmechanism employed in converting the blank into the desired article.

- What I claim is:

1. Cutting mechanism for forming blanks of thin sheet materialcomprising a die member adapted to support the sheet and being providedwith a centrally arranged aperture to receive the severed blank,zacutter support, said die and said support being arranged to haverelative axial movement, a. cutter carried by said support and extendingtherefrom towards said die member, a presser member encircling saidcutter and being slidably mounted on said support and bein! Operableupon movement of said support toward the die to press the marginalportion of the sheet against the face of the die, said cutter bladebeing formed on its extending edge with a plurality of teeth arranged topenetrate the sheet at a plurality of points upon contact of the bladewith the sheet, and to subsequently sever the sheet intermediate saidpenetrations. 4

2. Cutting mechanism for forming blanks of thin sheet materialcomprising a die member adapted to support the sheet and being providedwith a centrally arranged aperture, a support member movable axiallytoward and from said diemember, a presser member arranged intermediatesaici'die member and said support and being slidably mounted on saidsupport and being operable upon movement of said support toward the dieto press the marginal portion of the sheet against the face of the die,a cutter blade carried by said support and extending toward said die,said extending portion being encircled by said presser member and theedge of the blade being formed with a plurality of teeth arranged topenetrate the sheet at a plurality of points upon contact of the bladewith the sheet and upon further movement of the blade toward the die tosever the sheet intermediate said penetrations.

3. Cutting mechanism for forming blanks of thin sheet materialcomprising a die member adapted to support the sheet and being providedwith a centrally arranged aperture, a cutter support, said die andsupport being arranged to have relative axial movement, a cutter carriedby said support and extending therefrom toward said die member and beingformed with a plurality of teeth arranged, upon contact of the cutterwith the sheet, to penetrate said sheet at a plurality of points, and tosubsequently sever the sheet intermediate said penetrations, and meanscarried by said support and cooperable with the die member to draw thesheet radially and maintain the same in taut condition during thepenetration and severance of the sheet.

4. Cutting mechanism for forming blanks of thin sheet materialcomprising a stationary member of annular formation adapted tosupportthe sheet during the cutting operation, a movable member of annularformation, a cutter blade detachably secured to the movable member andextending therefrom toward said stationary member, the extending edge ofsaid blade being formed with saw-like teeth, with the cutting pointv ofeach tooth overlapping the base of the adjacent tooth.

5. Cutting mechanism for forming blanks of thin sheet materialcomprising a die member of annular formation adapted to support theblank during the cutting operation, a cutter carrier of annularformation arranged concentrically with said die member and being movabletoward and from the same, said carrier member being formed with acounterbore, a cutter blade of thin, flexible material detachablysecured in said counterbore and extending toward said die, saidextending portion of the cutter blade being provided with a plurality ofsaw-like teeth, with the point of each tooth arranged to overlap thebase of the adjacent tooth.

6. A cutting mechanism for forming blanks of thin sheet materialcomprising an annular die member, an annular cutter member provided withsaw-like teeth extending toward said die member, said members havingrelative axial movement, the teeth of the cutter member being formedwith the front and rear side edges thereof extending in the samedirection, and with the rear edge of each tooth overlapping the point ofthe adjacent tooth, whereby upon relative axial movement of saidmembers, the points of the teeth penetrate the sheet and subsequentlythe rear edges of the teeth sever the sheet interme diate saidpenetrations.

7. A cutting mechanism for forming blanks of thin sheet materialcomprising an annular die member, an annular cutter member, providedwith saw-like teeth extending toward said die member, with the cuttingpoint of each tooth overlapping the base of an adjacent tooth, and saidannular members having relative axial movement to bring said teeth anddie into and out of operative shearing relation.

8. A cutting mechanism for forming blanks of thin sheet materialcomprising an annular die member, an annular cutter carrier formed witha counter-bore, a cutter blade of thin, flexible material arranged insaid counterbore and having a toothed edge extending toward said diemember,

tive axial movement to bring said cutter blade and die into and outof-operative shearing relation, a ring member arranged in saidcounterbore within said cutter blade, and means operable to expand saidring to press said cutter blade radially outwardly against the wall ofsaid counterbore.

9. A cutting mechanism for forming blanks of thin sheet materialcomprising an annular die member, an annular cutter carrier providedwith saw-like teeth extending toward said die member, a presser ringarranged intermediate said die member and said cutter carrier member andbeing yieldingly supported by one of said members, said members havingrelative axial movement to bring the cutter member and the die into andout of operative shearing relation, said presser member being yieldinglycarried by one ISAAC L. WILCOX.

